Two new Apple handsets went on sale today and there are already reports that the iPhone 5S has sold out in many stores - mainly Apple ones. That means there will be plenty of people out there with one of the devices. There will be plenty with the cheaper iPhone 5C too, and so there will be many people who might encounter faults and issues with the new handsets.

A few of those faults will be covered by the warranty and many won't, but you might not know which is and which isn't before you head to a Genius Bar in an Apple Store to find out.

But Pocket-lint has seen an internal Apple document - one that is usually intended for employees - that outlines exactly that. It details the types of faults that might be encountered by iPhone 5S or iPhone 5C owners, and which ones are legitimately serviceable free of charge and which ones might incur a charge. It also lists a few that aren't serviceable at all.

The issues covered by the warranty, according to the document, include debris under the display glass or pixel anomaly, a bent enclosure for the iPhone 5S or iPhone 5 where there is no cracked glass or visible points of impact, or a single hairline crack to the front glass or back inlay (the bits at the top and bottom of the aluminium rear).

Problems not covered include liquid damage confirmed by the user, evidence of internal corrosion, any chips or fractures in the glass, LCD display fractures under the glass, or a damaged Lightning connector. Also not included in the warranty are extreme abrasions, puncture holes or missing or damaged buttons. Split enclosures and audio jack damage where the hole is plugged with foreign material are also a no-no.

Strangely a bent enclosure on an iPhone 5C is not eligible for service under the warranty even though the same fault on a 5S or 5 is.

Those issues completely ineligible for service are fairly obvious: a disassembled unit or one with missing parts, a phone with counterfeit or mismatched third-party parts, or a phone that has suffered catastrophic damage. In car terms it would be called a "write-off".

Many of these issues will be obvious, but if in doubt, we still advise contacting Apple anyway.